Planet Evaporation as a Window into Exoplanetary Origins

Informations projet

PEVAP

N° de convention de subvention: 853022

DOI

10.3030/853022

Projet clôturé

Date de signature de la CE 30 Octobre 2019

Date de début 1 Février 2020

Date de fin 31 Octobre 2025

Financé au titre de

• EXCELLENT SCIENCE - European Research Council (ERC)

Coût total

€ 1 464 320,00

Contribution de l’UE

€ 1 464 320,00

Coordonné par

IMPERIAL COLLEGE OF SCIENCE TECHNOLOGY AND MEDICINE
United Kingdom

Periodic Reporting for period 3 - PEVAP (Planet Evaporation as a Window into Exoplanetary Origins)

Période du rapport: 2023-02-01 au 2024-07-31

Résumé du contexte et des objectifs généraux du projet

We have discovered a large number of planets close to their host stars. In fact, we now know most stars host planets inside the orbit of Mercury in our own Solar System. Yet unlike the solar system terrestrial planets, these exoplanets often contain large atmospheres rich in hydrogen gas. It is currently an unsolved problem how these planets form or how the Earth sits within the zoo of all possible planets. Given many of these planets are extremely highly irradiated by their host stars, they are vulnerable to having their atmospheres heated up and lost to space through a process known as "photoevaporation".

It is thought that this photoevaporation process is responsible for many of the features detected in the exoplanet population today. Thus, rather than using the observed exoplanets to inform about their origins, we need to account for this photoevaporation process. Thus, in this project, we will develop new photoevaporation models and then use them to determine how the planets evolved into those we see today.

Our objectives are:

1. What are the mass-loss rates and photoevaporative flow structures for the full spectrum of observed planets?
2. How can we use observations of photoevaporating planets to learn about their compositions and histories?
3. How does photoevaporation affect and control the evolution of exoplanets and their atmospheres?

Travail effectué depuis le début du projet jusqu’à la fin de la période considérée dans le rapport et principaux résultats atteints jusqu’à présent

So far, we have begun developing new photoevaporation models for atmospheres that contain more elements than hydrogen. We have developed a new computer code that can simulate the photoevaporative outflows from these planets and have applied it to hot terrestrial planets where their surfaces are melted. Furthermore, we have used our models for the photoevaporation of hydrogen atmospheres to understand the evolution of these planets. By building a model of how the hydrogen atmospheres of exoplanets evolve in time, we have used it to unwind the billions of years of evolution that exoplanets have undergone. In doing so, we have uncovered how many of the observed exoplanets formed. We found that most observed exoplanets did not form like those in our Solar System, rather they formed through a previously unidentified pathway where they grew quickly acquiring a small amount of primordial gas close to their host stars.

Progrès au-delà de l’état des connaissances et impact potentiel prévu (y compris l’impact socio-économique et les conséquences sociétales plus larges du projet jusqu’à présent)

In the project's next phase, we expect to apply the same statistical analysis to the hydrogen-dominated atmospheres to atmospheres more akin to the terrestrial planets in our Solar-System. In doing so, we will be able to put Earth in the context of exoplanets and answer the question of how rare we really are.

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